Conventional keybutton-equipped devices typically have a keypad which is mounted inside the case and is provided with keybuttons exposed on the surface and penetrating through holes in the case equipped for the keybuttons.
Japanese utility model application laid-open No. 5-16571 (1993) discloses a keypad structure that switch-button member (keypad) is mounted inside the case and only the buttons are exposed on the surface and penetrating through holes in the case equipped for the buttons. In this structure, it is troublesome to assemble and disassemble the switch-button member.
Also, Japanese patent application laid-open No. 8-148054 (1996) discloses a key structure that switch-button member (keypad) is mounted inside the case, only the buttons are exposed on the surface and penetrating through holes in the case equipped for the buttons, and inside of the case is water-proofed by using covering sheet. In this structure, it is still troublesome to assemble and disassemble the switch-button member. Also, it allows dust or water to get into the case and to be left there. Further, the covering sheet may incur corrosion.
Thus, in the conventional keybutton-equipped devices, there is a problem that it is very troublesome to mount/remove the keypad. Also, they allow some liquid or dust to get into the case from a clearance between the hole in the case and the keybutton.